Process of forming methyl ester of acetyl salicylic acid.



mixed, in the siren sites PATENT LUMBER/I THORP, F

DETROIT, MICHIGAN.

Ii'o Drawing.

In carrying out my improved method,

methyl salicylate and acetic anhydrid are general ratio of one equivalent of methyl salicylate to one and one-half equivalents of acetic anhydrid, but prefer- To separate the product, to the solution, preferably inthe ratio 'of' eleven parts by weight of alcohol to ten parts by Weight of the methyl sulicylate. This exact proportion is not, however, absolutely essential. To the solution thus obtained hot water is then added until a faint, permanent turbidity results. After coolmg, the product maybe separated by filtra- What I claim as my invention is:

l. he process of forming the methyl ester of acetyl salicylic acid, comprising the mixing of methyl salicylate and acetic anydricl in the presence of an alkali metal alcohol is added acetate as a catalyzing agent.

2. The process of forming the methyl ester of acetyl salicylic acid, comprising the mixing of methyl salicyletc and acetic anhydrid in the presence of an alkali metal ace- Speciiication of Letters lPatent. .epplication filed August 21,

Patented Feb. i2. 11ers,

191a. Serial no. 116,180.

ably with about per cent. excess of the acetic anhydrid. That is to say, the general ratio of the methyl selicylate to the acetic anhydrid will be 10 to 15 but preferably the proportions will be 10 to 16.5, giving" a consiclcrable excess of the cheaper material. I have discovered. that the reaction is greatly facilitated by the use of a catalyzing agent, preferably amalkaline acetate, such for instance as anhydrous sodium acetate. Other catalyzers may, however, be substituted, such for instance as zinc chlorid or sulfuric acid.

The materials are mixed at ordinary temperah and are then heated to 95 C., and riocl of preferably from ten to iours, resulting in the formation of a homogeneous mess, the reaction being as follows:

tate catalyzing agent, heating the materials and precipitating the product with dilute alcohol.

3. The process of forming the, methyl ester of acetyl salicylic acid, comprising the mixing of methyl saiicylate and acetic anhydrid in the general ratio of oneequivalent of methyl salicylete to sli 'htly' more than one equivalent or" acetic anhydrid, adding an alkali metal acetate as catalyzing agent, heating the materials to a tem erature be- (1. rom. itenmto twenty hours, addingalcohol and subsequently adding" hot Water until e slight permanent turbidity is attained, cooling" the lution and separating the product by fiitrw tion.

In testimony whereof I aiiix my signature.

LAMBERT THORP. 

